Wind turbine blades are generally manufactured in the form of numerous separate components which are adhesively bonded together to form the greater wind turbine blade structure. Accordingly, a large part of the strength of the wind turbine blade is dependent on the structural integrity of the adhesive bond lines between the different components. A single bondline failure between blade components can result in a complete failure of the blade structure, requiring costly repair and/or replacement operations.
As the strength of an adhesive bond line is related to the height of the bond line between component surfaces, great care is taken to ensure that a minimum bond line height is maintained between component surfaces during bonding.
For example, in the case of a bondline between blade shell surfaces, this can require accurate positioning and measurement of bondline heights for the duration of a shell closing operation.
In the case of blade components which are bonded in a male-female connection, where the adhesive bond line extends along the male-female interface between components, accurate positioning of the male component relative to the female component must be performed, to ensure that the bondline height is maintained around the entire interface between components.
For example, with reference to FIG. 5(a), a male component in the form of a shear web body 70 is partly received within a female component in the form of a web foot 72 for a shear web, an adhesive 74 provided in the female component 72 to bond the shear web body 70 to the web foot 72. After insertion of the shear web body 70 into the web foot 72, unless the positioning and placement of the shear web body 70 is portion of the web foot 72, FIG. 5(b). In this case, the bondline of adhesive 74 between the shear web body 70 and the web foot 72 is not of equal height around the entire interface between the components, resulting in a bond of reduced strength along at least one side of the interface, increasing the risk of bond failure.
Accordingly, such bonding operations impose relatively strict accuracy requirements, and can often require over-dimensioning of component properties, e.g. minimum bondline height, to account for any margin of error or accuracy variations during the positioning process.
It is an object of the invention to provide a system and method for the bonding of wind turbine blade components which addresses the above issues.